Give a Codex Skill One Example It Must Reject
A skill can look excellent on the example it was written for. A nearby request outside its scope reveals whether its boundary is clear.
For a skill that validates a sales CSV, add one accepted fixture and one request to email the resulting report to customers. The second request requires a different authorization path. Ask Codex to explain the boundary and observe the tools it actually invokes.
Keep the rejection example beside the successful one. It helps future edits preserve the distinction between preparing an artifact and sending it. A skill description and instruction file guide the agent, but consequential actions still need appropriate tool permissions and checks. The example should test that behavior rather than reward a reassuring sentence.
